Process for manufacturing 1-aminonaphthalene-8-carboxylic acid



Patented 0a. 18, 1927..

UNITED STATES 1,646,290 PATENT OFFICE.

RICHARD HEBZAND FRITZ SCHULTE, OF FRANKFORT-ON-THE-MAIN, GERMANY, AS-

SIGNORS T0 GRASSELLI DYESTUFF CORPORATION, OF NEW YORK, N. Y., A COR- PORATIQN OF DELAWARE.

PROCESS FOR MANUFACTURING l-AMINONAPHTHALENE-S-CARBOXYLIC ACID.

in Drawing. .a pucauon am July 12, 1926, Serial No. 122,030, and in Germany November 29, 1924..-

We have found anew and original rocess for manufacturing the l-aminonapht alene- S-carboxylic acid in a pure state with an almost quantitative yield and at comparatively lowcosts. Hitherto this acid could not be produced on a technical scale.

Our new rocess consists in allowing an alkaline actmg agent to react at elevated temperatures on 8-cyannaphthalene-1-sulfomc acid.

The chemical reaction which takes runs probably as follows:

1 In the first phase of the reaction probably the cyanogen group is saponified to the carplace ON SOIH W thaa-na hthomlde lone-1421 201110 l-siillonlo acid.

In carrying out our processpractically, caustic alkalies in aqueous or alcoholic solution or alkaline earth metal compounds, preferably milk of lime, may be used either at ordinary pressure or in a closed vessel at elevated pressure.

The starting material for the process,

8-cyannaphthalene-1-sulf0nic acid, is A easily cyannaphthalene-l-sulfonic acid is very easily soluble in water and shows a strong acid reaction.

The newprocess may be illustrated by the following examples, the parts being by The free S-cyahnaphthalene-lnanie the inner anhydrideof el-aminonapht alene-8-carboxylicacid, known in the in the second phase the sulfo oup 1s split off and a rin 'is formed,

literature as naphthostyril. This latter compound is easily sapomfied' by the action of dilutealkalies to the l-aminonaphthalene-S- carboxylic acid. 1

The following formula illustrate the course of the reactions:

naphthoctyrll.

l-omlnonaphn atweight and all temperatures in centigrade de rees:

wa/mple 1.40 parts ofcaustic potash and 5 parts of water are heated in a suitable vessel until the mass is dissolved. Then 10 parts of the sodium salt of the 8-cyannaphthalene-l-sulfonic acid are introduced at about heating is continued under reflux. The temperature is slowly increased while stirring well to about ISO-200. Higher temperatures preferably are avoided, as at higher The vessel is closed and thentemperatures ammonia is split OK and undesirable by-products are formed.

When the reaction is finished, the product of reaction thus obtained consists almost entirely of the potassium salt of the naphtho- 'styril, which may be isolated directly by diluting the mass with common salt solution and ltering the separated potassium salt. From this salt the free naphthostyril is easily obtained by acidifying. It is thus obtained in an almost pure state; when recrystallized from alcohol or glacial acetic acid it shows a meltin point of 180181 and itis identical in all 1ts properties with the prodnot, described by Eckstrand (see Journal fiir prakt. Chemie (2), 38 (1888) page boxylic acid is isolated by filtration in a pure state with an almost quantitative yield. It

' is identical with the acid described by Eek- I carboxylic acid. It ma Y concentrated strand (l. c.) The aforesaid intermediate product of the \process, namely the 8-naphthamide-l-sulfonic acid, can be isolated by interru ting the melt after about an hour and di utin the mass with water, until a alkaline solution is obtained. The potassium salt of the S-naphthamide-lsulfonic acid separates, becauseit is difficultly soluble in such a solution. It crystallizes from water in rhombic leaflets.

This intermediate product may. also advantageously be produced by heating the 8- cyannaphthalene-l-sulfonic acid in the form of a suitable salt with a caustic soda solution of for instance 30-40 B. for some time at 100-120", with or without the addition of alcohol. The sodium salt of the thus pro duced B-naphthamiiie-l-sulfonic acid crystallizes, when cooled down, in rhombic leaflets.

By melting the 8-naphthamide-1-sulfonic acid with concentrated caustic alkalies or even with alkaline acting agents, for instance, with sodium formate or sodium acetate, at higher temperatures, it is converted into na hthostyril.

But if the 8-naphthamide-1-sulfonic acid is saponified with dilute acids, ammonia is split off and the 8-carboxynaphthalene-1-sulfonic acid is formed.

Example 2.4= arts of caustic potash and 6 parts of methy 'c alcohol are eated for .some time at 80-100"; at this temperature one part of the sodium salt of the 8-cyannaphthalene-l-sulfonic acid is introduced. Then methyl alcohol is slowly distilled off, until the temperature reaches 130-150. At this temperature heating is continued for some hours under reflux. The product of reaction, thus obtained, consists almost entirely in the form of the inner anhydride of 1-aminonaphthalene-8- be isolated as such, or it may be converte into the acid itself in the manner describedabove in Example 1.

Example 3.-In an autoclave 10 parts of the sodium salt of the B-cyannaphthalene-lsulfonic acid are introduced at ordinary temperatures into 40 parts of causticsoda solution of 40 Bi Then the mass is heated for 6-10 hours at 150200, corresponding to a pressure of 10-15 atmospheres. The prodnot of reaction thus obtained is the diflicultly soluble sodium salt of l-aminonaphthalene- 8-carboxylic acid. After cooling down, the

mass is diluted with common salt solution and the sodium salt of the carboxylic acid is isolated by filtration. It may be purified by recrystallizin it from a diluted common salt solution, or t e free acid may be obtained by acidifying. It is identical with the acid described above.

E trample .,..-1 part of the sodium salt,-- or of any suitable salt,-of S-cyannaphthalene-l-sulfonic acid is heated with 15 parts of milk of lime of 25 B. for some hours at 200-250 in an autoclave, while stirrin The 1-aminonaphthalene-8carboxylic aci thus formed,'remains in solution in the form of its easily soluble calcium-salt. The mass is diluted with Water, filtered off, and the free acid is isolated from the filtrate by acidifying it.

We wish it to be understood, that when working in an autoclave the pressure corresponds functionall to the tension of the reacting agent and t e temperature applied.

This application contains subject matter described and claimed in our coending apphcation Seriall No. 190,127, file May 9, 1927.

We claim: I

1. Process for the manufacture of a l-amino-naphthalene-8-carboxylic acid compound which' com rises treating an S-cyannaphthalene-l-sul onic acid compound with an alkaline-acting agent at a temperature greater than C. and not substantially above 200 C.

2. Process for the manufacture of a l-amino-naphthalene-8-carboxylic acid compound which comprises treatin a salt of 8-cyannaphthalene-l-sulfonic acid with an alkaline-actin agent at a temperature greatgidotgiacn 100 and not substantially above 3.' Process for the manufacture of a l-amino-naphthalene-8-carboxylic acid compound which comprises treatin a salt of 8-cyannaphthalene-1-sulfonic acld with an alkaline acting agent in an autoclave at a temperature greater'than 100 C. and not substantially greater than above about 200 C.

4 Process for the manufacture of a l-am1no-naphthalene-8carboxylic acid compound which comprises treat-in a salt of '8-cyannaphthalene-l-sulfonic acid with a a temperature greater than 100 C. and not acid by carefully acidifying the reaction mixture. 7

7. In a new process for the manufactureof a 1-aminonaphthalene-S-carboxylic acid compound which involves reacting with a caustic alkali at a temperature greater than 100 C. and not substantially above 200 C. on a salt of 'B-cyannaphthalene-l-sulfonic acid, the step which consists in isolating the l-amino; naphthalene-8-carboxylic acid compound in the form of its inner anhydride.

8. Process for the manufacture of a l-amino-naphthalene-8-carboizylic. acid compound which comprises treating a salt of 'tures'. v

S-cyannaphthalene-l-sulfonic acid with a caustic alkali at a temperature greater than 100 C; and not substantially above 200 C., and isolating from the resulting reaction mixture a .l amino-naphthalene-8-carboxylic acid compound. I

9. Process for the manufacture of a 1-amino-naphthalene-S-carboxylic acid compound which com rises treating an' 8-cyannaphthalene-l-sul onic acid compound in alcoholic solution with an alkalme-actin agent at 'a temperature above 100 C. an not substantially above about 150 C.

In testimony whereof, we aflix our signa- RIGHARD HERZ. FRITZ SCHULTE. 

